Commonly-owned U.S. Pat. Nos. 5,677,390, 5,686,538, 5,767,203, 5,852,131, 5,852,132, 5,916,978, 6,133,381, 6,207,765, 6,232,393, 6,232,408, 6,235,831, 6,235,844, 6,326,439, and 6,521,714 describe what is believed to be the best known prior process technology for producing brominated styrenic polymers such as brominated polystyrene having the best known properties of any previously-known brominated styrenic polymer. In this connection, the terms “brominated styrenic polymer” and “brominated polystyrene” as used in the specification and in the claims hereof refer to a brominated polymer produced by bromination of a pre-existing styrenic polymer such as polystyrene or a copolymer of styrene and at least one other vinyl aromatic monomer, as distinguished from an oligomer or polymer produced by oligomerization or polymerization of one or more brominated styrenic monomers, the properties of the latter oligomers or polymers typically being considerably different from brominated polystyrene in a number of respects.
Over the years considerable efforts have been made by various parties to improve upon the properties of brominated styrenic polymers, such as improved melt flow and/or low color values. Despite their best efforts, it appears that no party has been able to produce or provide a brominated styrenic polymer having the high melt flow values and/or low color values, much less the combination of excellent properties, of the brominated styrenic polymers producible and provided by this invention. Nor has a prior party found the processing relationships that make possible the production of such improved brominated styrenic polymers.